i hav done prior research n got different answers. Maybe u guys can help me. Can u mix regular 87 octane n premium 91 octane ? I have ask a couple of mechanics and they have said its ok to mix those 2 grade. But i hav read online that if u do tha it will causes problem to the engine. So which is the proper answer ?!?! i ususally put only premium in my car but after the stom i had no choice but to put regular. I wanna go back to prem. But i dont know if i can mix the gas.